Method for simultaneously preparing 2, 6-dichloro-4-trifluoromethylaniline and m-trifluoromethylaniline

Abstract

The invention discloses a method for simultaneously preparing 2, 6-dichloro-4-trifluoromethylaniline and m-trifluoromethylaniline, which comprises the following steps: carrying out ammoniation reaction by using 3, 4, 5-trichlorotrifluorotoluene as a raw material and pyrrolidone as a solvent to obtain the 2, 6-dichloro-4-trifluoromethylaniline; 2, 3-dichloro-5-trifluoromethylaniline contained in the residual liquid after rectification is further subjected to hydrogenation reaction to prepare the m-trifluoromethylaniline, meanwhile, preparation of the 2, 6-dichloro-4-trifluoromethylaniline and the m-trifluoromethylaniline is achieved, and generation of three wastes is reduced.

Description

Technical Field

[0001] The invention belongs to the field of fine chemical production, and specifically relates to a method for simultaneously preparing 2,6-dichloro-4-trifluoromethylaniline and m-trifluoromethylaniline. Background Art

[0002] 2,6-Dichloro-4-trifluoromethylaniline is an important intermediate for medicine and pesticides because of its unique biological activity of fluorinated aromatic compounds and its easy combination with acid to form corresponding salts. Its diazonium salt can condense itself or with other compounds to generate many useful dyes, new high-efficiency insecticides and herbicides, such as fipronil, fluvalinate, flubendiamide and other pesticides.

[0003] At present, the mainstream industrial process of 2,6-dichloro-4-trifluoromethylaniline reported in the literature uses para-chlorotrifluorotoluene as raw material, and obtains 2,6-dichloro-4-trifluoromethylaniline through ammoniation and chlorination.

[0004] 1) Amination: p-Chlorotrifluorotoluene is used as the raw material, and liquid ammonia is reacted with solvent and catalyst under high temperature and high pressure to obtain p-trifluoromethylaniline.

[0005] For example, Chinese patent CN1 02643202A discloses a "method for producing p-trifluoromethylaniline", in which trifluorotoluene is used as raw material, the solvent is ethanol, and the catalyst is composed of cuprous chloride and potassium fluoride, which react with ammonia at high temperature and high pressure to obtain p-trifluoromethylaniline. The conversion rate of p-chlorotrifluorotoluene in the amination reaction is about 50%.

[0006] 2) Chlorination: Add solvent to trifluoromethylaniline and pass chlorine gas intermittently to obtain 2,6-dichloro-4-trifluoromethylaniline.

[0007] For example, Chinese patent CN100534975C discloses a "method for producing 2,6-dichloro-4-trifluoromethylaniline". In this patent, a para-trifluoromethylaniline raw material is added to a solvent, wherein the reaction solvent is ethylene dichloride. Chlorine gas is introduced into a reaction kettle for chlorination reaction to generate a mixture of 2,6-dichloro-4-trifluoromethylaniline. After the solvent is removed, an alkali is added for neutralization to obtain a crude 2,6-dichloro-4-trifluoromethylaniline. The finished product is refined by vacuum distillation, and the product purity is above 99.5%.

[0008] Meta-trifluoromethylaniline is an important chemical intermediate. Its amino group has strong reactivity and can be used to synthesize a series of compounds. It is widely used in the fields of pesticides, medicines, etc.

[0009] 1) Medical field: 3-Trifluoromethylaniline can be used as a raw material to synthesize the antimalarial drug mefloquine, the anti-inflammatory and analgesic drugs flufenamic acid and niflumic acid, the diuretics bendroflumethiazide and hydroflumethiazide, the antidepressant fluvoxamine, the analgesic flofenine, and the anti-inflammatory drugs flufenamic acid butyl, moniflumate, and flusalen; the skin fungicide triflumuron TFC; the anti-prostate drug flunitramide and a variety of strong sedatives and antipsychotic drugs fluphenazine and triflupromazine, etc.

[0010] 2) Pesticide field: 3-Trifluoromethylaniline can be used to synthesize 3-trifluoromethylacetophenone oxime, an intermediate of trifloxystrobin and trifluanid, 3-trifluoromethylbenzoic acid methyl ester, an intermediate of cyanamide, and 3-trifluoromethylphenol, an intermediate of fluazifop-butyl. It is also an intermediate of fluazifop-butyl, fluazifop-butyl, fluazifop-butyl, and fluazifop-butyl pesticides.

[0011] Chinese patent CN103787896A discloses a "method for synthesizing m-trifluoromethylaniline", which uses trifluorotoluene as raw material, undergoes mixed acid nitration, and hydrogenation reduction under normal pressure to obtain m-trifluoromethylaniline. A cheap nickel catalyst is used instead of commonly used precious metal catalysts such as palladium and platinum to reduce production costs. Methanol used as a solvent is easy to recover and can be recycled, reducing the emission of organic matter in the production process. However, the nitration reaction in this method will produce a large amount of mixed acid, which is difficult to handle.

[0012] In summary, there is currently no process for preparing 2,6-dichloro-4-trifluoromethylaniline and m-trifluoromethylaniline at the same time. Summary of the invention

[0013] The invention aims to provide a method for simultaneously preparing 2,6-dichloro-4-trifluoromethylaniline and m-trifluoromethylaniline. In the process of preparing 2,6-dichloro-4-trifluoromethylaniline, the generated aminated isomer byproduct 2,3-dichloro-5-trifluoromethylaniline is used to prepare m-trifluoromethylaniline with wide applications, thereby improving the economic benefits. The whole process has the advantages of high yield, less three wastes, strong safety, etc., and is a green process with high selectivity, strong economy and environmental friendliness, which has great guiding significance for industrial production.

[0014] To achieve the above purpose, the technical solution of the present invention is as follows:

[0015] A method for simultaneously preparing 2,6-dichloro-4-trifluoromethylaniline and m-trifluoromethylaniline comprises the following steps:

[0016] 1) Amination reaction

[0017] 3,4,5-trichlorobenzotrifluoride is used as a raw material, mixed evenly with a pyrrolidone solvent, added to an autoclave, ammonia gas is introduced, the temperature is raised to the reaction temperature and then kept warm for reaction, the central control sampling is used to detect the gas phase qualitative content of 3,4,5-trichlorobenzotrifluoride in the reaction liquid is less than 1% to end the reaction, the pressure is released after the reaction is completed, and the reaction solution obtained after the pressure release is filtered to obtain a filtrate and a filter cake respectively;

[0018] The obtained filtrate is filtered and distilled to obtain pyrrolidone solvent and 2,6-dichloro-4-trifluoromethylaniline in sequence, and the remaining residual liquid is stored for later use;

[0019] The pyrrolidone solvent is at least one of N-methylpyrrolidone, N-propylpyrrolidone and N-butylpyrrolidone, and the amount of the pyrrolidone solvent is 1 to 3 times the weight of 3,4,5-trichlorotrifluorotoluene;

[0020] The reaction temperature is 170-190°C, and the reaction pressure is 7-10MPa;

[0021] The molar ratio of 3,4,5-trichlorotoluene trifluoride to ammonia is 1:25-40;

[0022] 2) Hydrogenation reduction;

[0023] The residual liquid obtained in step 1) and hydrogen are simultaneously introduced into a fixed bed reactor adjusted to the reaction temperature and reaction pressure for hydrogenation reduction reaction, and during the reaction, samples are taken to detect the gas phase qualitative content of 2,3-dichloro-5-trifluoromethylaniline in the reaction liquid until it is less than 0.5%, and the hydrogenated material after the reaction is completed is collected and distilled to obtain a m-trifluoromethylaniline product with a purity of more than 99wt%; the fixed bed reactor is filled with a catalyst;

[0024] The catalyst is platinum carbon, wherein the platinum content is 1 to 5 wt%, the platinum carbon particle size is 0.5 to 1.0 mm, and the platinum carbon filling height is 10 to 15 cm;

[0025] The residual liquid feed rate is 0.5-3.0 mL / min, and the hydrogen feed rate is 50-100 mL / min;

[0026] The reaction temperature is 100-120° C., and the reaction pressure is 0.1-0.5 MPa.

[0027] Preferably, in step 1), the filter cake obtained by filtration is dried, dissolved in water, adsorbed by resin, concentrated, and dried to recover the byproduct ammonium chloride.

[0028] Preferably, the resin is at least one of XDA-1G, XDA-6, XDA-8, and XDA-200, preferably XDA-1G.

[0029] Preferably, the amount of water added for dissolution is 2 to 5 times the weight of the filter cake after drying.

[0030] Preferably, in step 1), the reaction time is 5 to 10 hours.

[0031] Preferably, in step 1), ammonia gas is collected during the pressure release process and compressed for reuse.

[0032] Preferably, in step 2), the fixed bed reactor is made of one of Hastelloy, titanium and zirconium, and has a reactor diameter of 30 to 40 mm and a length of 30 to 40 cm.

[0033] Preferably, in step 2), the reaction tail gas is first absorbed by water to obtain by-product hydrochloric acid, and then dried and compressed to compress the hydrogen for reuse.

[0034] Preferably, the purity of the obtained by-product hydrochloric acid is 28wt% to 31wt%.

[0035] In the process of preparing 2,6-dichloro-4-trifluoromethylaniline, 3,4,5-trichlorobenzotrifluoride is used as a raw material, pyrrolidones are selected as solvents, and the filtrate obtained after the reaction is rectified to obtain pyrrolidones solvent and 2,6-dichloro-4-trifluoromethylaniline in sequence, and the obtained pyrrolidones solvent can be repeatedly used after being recovered. Ammonium chloride, a byproduct produced by the reaction, is retained in the filter cake and is recovered for use after a series of operations.

[0036] More importantly, the present invention has identified that the amination byproduct in the residual liquid obtained at the end has the structure of 2,3-dichloro-5-trifluoromethylaniline. The reaction equation of the amination reaction is as follows:

[0037]

[0038] After research, the present invention selects a suitable catalyst, uses platinum carbon as a catalyst, wherein the platinum content is 1-5wt%, the platinum carbon particle size is 0.5-1.0mm, and the platinum carbon filling height is 10-15cm. The residual liquid containing 2,3-dichloro-5-trifluoromethylaniline is subjected to a hydrogenation reduction reaction to prepare widely used m-trifluoromethylaniline, which effectively realizes the recycling of resources. The reaction equation of the hydrogenation reaction is as follows:

[0039]

[0040] Compared with the prior art, the present invention has the following beneficial effects:

[0041] The invention determines the structure of byproducts generated in the preparation process of 2,6-dichloro-4-trifluoromethylaniline through a series of analyses, and selects appropriate platinum carbon as a catalyst to prepare 2,3-dichloro-5-trifluoromethylaniline, a byproduct generated in the preparation process of 2,6-dichloro-4-trifluoromethylaniline, into m-trifluoromethylaniline, thereby effectively realizing full utilization of resources in the preparation process of 2,6-dichloro-4-trifluoromethylaniline and reducing generation of three wastes. The invention is a green process with high selectivity, strong economy and environmental friendliness, and has great guiding significance for industrial production. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Figure 1 This is the GC detection chromatogram of the reaction in Example 1 of the present invention.

[0043] Figure 2 This is the GC detection chromatogram of the 2,6-dichloro-4-trifluoromethylaniline standard obtained in Example 1 of the present invention.

[0044] Figure 3 This is the GC chromatogram in the GC-MS detection during the reaction of Example 1 of the present invention.

[0045] Figure 4 This is the MS chromatogram of the compound at 9.867 min in the GC-MS detection during the reaction of Example 1 of the present invention.

[0046] Figure 5 This is the MS chromatogram of the compound at 10.925 min in the GC-MS detection during the reaction of Example 1 of the present invention.

[0047] Figure 6 2,6-dichloro-4-trifluoromethylaniline obtained in Example 1 of the present invention 1 H-NMR chromatogram.

[0048] Figure 7 2,3-dichloro-5-trifluoromethylaniline obtained in Example 1 of the present invention 1 H-NMR chromatogram. DETAILED DESCRIPTION

[0049] The present invention is further described below in conjunction with examples and drawings. To facilitate understanding of the present invention, the present invention lists examples as follows. Those skilled in the art should understand that the examples are only to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0050] Example 1

[0051] A method for simultaneously preparing 2,6-dichloro-4-trifluoromethylaniline and m-trifluoromethylaniline, the specific steps comprising:

[0052] 1) Amination reaction: 100.00 g 3,4,5-trichlorobenzotrifluoride (0.40 mol) and 100.00 g N-methylpyrrolidone were mixed and added to an autoclave, 170.00 g ammonia (9.88 mol) was introduced, and the temperature was raised to 185° C. and 7.0 MPa for 9 hours. The gas phase qualitative content of 3,4,5-trichlorobenzotrifluoride in the reaction solution was sampled and detected to be 0.50%. After the reaction was completed, the pressure was released, and the ammonia was compressed and reused; the reaction solution obtained after the pressure release was filtered,

[0053] The obtained filtrate was distilled to obtain 71.00 g of N-methylpyrrolidone and 74.00 g of 2,6-dichloro-4-trifluoromethylaniline with a purity of 99.10 wt %, and the remaining about 25.00 g of residual liquid containing 2,3-dichloro-5-trifluoromethylaniline was stored for later use; the yield of 2,6-dichloro-4-trifluoromethylaniline was 80.30%;

[0054] The obtained filter cake is dried to recover N-methylpyrrolidone, and the obtained solid is dissolved in water, the amount of water added is twice the weight of the dried solid, and then the organic matter is adsorbed by XDA-1G resin, concentrated, filtered, dried, etc., to obtain a byproduct ammonium chloride with a purity of 99.50wt%;

[0055] 2) Hydrogenation reduction: A Hastelloy fixed bed reactor with a diameter of 30 mm and a length of 30 cm was filled with a 10 cm high platinum-carbon catalyst. After sealing, the preheater and the reactor were heated to 100 °C. The residual liquid containing 2,3-dichloro-5-trifluoromethylaniline and hydrogen were simultaneously introduced into the Hastelloy fixed bed reactor at a rate of 0.5 mL / min and 50 mL / min, respectively. The reaction pressure was adjusted to 0.50 MPa by a back pressure valve. The feed reaction was continued, and the 2,3-dichloro-5-trifluoromethylaniline in the reaction liquid was detected by sampling at the same time. -The qualitative content of trifluoromethylaniline in gas phase is 0.20% to terminate the reaction, the reaction tail gas is first absorbed by water to obtain a by-product hydrochloric acid with a purity of about 30wt%, and then the hydrogen is compressed and reused through drying and compression operations, and the hydrogenation reduction material after the reaction is collected and distilled to obtain 11.28g of m-trifluoromethylaniline product with a purity of 99.20wt%, and the yield of m-trifluoromethylaniline is about 17.50%; the platinum content in the platinum-carbon catalyst is 1.0wt%, and the particle size of the platinum-carbon catalyst is 0.5N1.0mm.

[0056] The reaction solution obtained in step 1) was subjected to GC analysis. The results were as follows: Figure 1 As shown, the GC analysis results of the 2,6-dichloro-4-trifluoromethylaniline standard are as follows Figure 2 As shown, compared Figure 1 and Figure 2The analysis results show that in the reaction solution obtained in step 1), the compound at 10.313min is 2,6-dichloro-4-trifluoromethylaniline, and the compound at 11.251min is an unknown substance.

[0057] The reaction solution obtained in step 1) is subjected to GC-MS analysis (the analysis method is exactly the same as the GC analysis method), and the results are as follows: Figure 3 , Figure 4 , Figure 5 , it was concluded that the molecular weight of the compounds at 9.867min and 10.925min in the GC-MS spectrum was 230, and they contained two chlorines, and both were dichlorine-containing isomers (the compounds at 9.867min and 10.925min in the GC-MS spectrum corresponded to the compounds at 10.313min and 11.251min in the GC spectrum, respectively);

[0058] The compound at 11.261 min in the GC spectrum was separated by column chromatography and reacted with 2,6-dichloro-4-trifluoromethylaniline 1 H-NMR analysis, the results are as follows Figure 6 and Figure 7 Combined with the reaction principle, it was concluded that the compound with an activity of 11.261 min was 2,3-dichloro-5-trifluoromethylaniline.

[0059] Example 2

[0060] A method for simultaneously preparing 2,6-dichloro-4-trifluoromethylaniline and m-trifluoromethylaniline, the specific steps comprising:

[0061] 1) Amination reaction: 100.00 g 3,4,5-trichlorobenzotrifluoride (0.40 mol) and 150.00 g N-methylpyrrolidone were mixed and added to an autoclave, 140.00 g ammonia (8.14 mol) was introduced, the temperature was raised to 180° C. and 7.5 MPa, and the reaction was carried out for 10 hours. The gas phase qualitative content of 3,4,5-trichlorobenzotrifluoride in the reaction solution was sampled and detected to be 0.65%. After the reaction was completed, the pressure was released, and the ammonia was compressed and reused; the reaction solution obtained after the pressure release was filtered;

[0062] The obtained filtrate was distilled to obtain 70.00 g of N-methylpyrrolidone and 72.54 g of 2,6-dichloro-4-trifluoromethylaniline with a purity of 99.20 wt %, and the remaining about 26.50 g of residual liquid containing 2,3-dichloro-5-trifluoromethylaniline was stored for later use; the yield of 2,6-dichloro-4-trifluoromethylaniline was 78.80%;

[0063] The obtained filter cake is dried to recover N-methylpyrrolidone, and the obtained solid is dissolved in water, the amount of water added is twice the weight of the dried solid, and then the organic matter is adsorbed by XDA-1G resin, concentrated, filtered, dried, etc., to obtain a byproduct ammonium chloride with a purity of 99.50wt%;

[0064] 2) Hydrogenation reduction: A Hastelloy fixed bed reactor with a diameter of 30 mm and a length of 30 cm was filled with a 10 cm high platinum-carbon catalyst. After sealing, the preheater and the reactor were heated to 105°C. The residual liquid containing 2,3-dichloro-5-trifluoromethylaniline and hydrogen were simultaneously introduced into the Hastelloy fixed bed reactor at a rate of 1.0 mL / min and 60 mL / min, respectively. The reaction pressure was adjusted to 0.35 MPa by a back pressure valve. The feed reaction was continued, and the 2,3-dichloro-5-trifluoromethylaniline in the reaction liquid was detected by sampling at the same time. -The qualitative content of trifluoromethylaniline in gas phase is 0.35% to terminate the reaction, the reaction tail gas is first absorbed by water to obtain a by-product hydrochloric acid with a purity of about 30wt%, and then the hydrogen is compressed and reused through drying and compression operations, and the hydrogenated reduction materials at the end of the reaction are collected and distilled to obtain 12.11g of m-trifluoromethylaniline product with a purity of 99.25wt%, and the yield of m-trifluoromethylaniline is about 18.80%; the platinum content in the platinum-carbon catalyst is 1.5wt%, and the particle size of the platinum-carbon catalyst is 0.5N1.0mm.

[0065] Example 3

[0066] A method for simultaneously preparing 2,6-dichloro-4-trifluoromethylaniline and m-trifluoromethylaniline, the specific steps comprising:

[0067] 1) Amination reaction: 100.00 g 3,4,5-trichlorobenzotrifluoride (0.40 mol) and 200.00 g N-propylpyrrolidone were mixed and added to an autoclave, 200.00 g ammonia (11.63 mol) was introduced, the temperature was raised to 190° C. and 9.5 MPa for 6 hours, and the gas phase qualitative content of 3,4,5-trichlorobenzotrifluoride in the reaction solution was sampled and detected to be 0.45%. After the reaction was completed, the pressure was released, and the ammonia was compressed and reused; the reaction solution obtained after the pressure release was filtered;

[0068] The obtained filtrate was distilled to obtain 70.50 g of N-propylpyrrolidone and 73.50 g of 2,6-dichloro-4-trifluoromethylaniline with a purity of 99.15 wt %, and the remaining about 25.50 g of residual liquid containing 2,3-dichloro-5-trifluoromethylaniline was stored for later use; the yield of 2,6-dichloro-4-trifluoromethylaniline was 79.80%;

[0069] The obtained filter cake is dried to recover N-propyl pyrrolidone, and the obtained solid is dissolved in water, the amount of water added is twice the weight of the dried solid, and then the organic matter is adsorbed by XDA-1G resin, concentrated, filtered, dried, etc., to obtain a byproduct ammonium chloride with a purity of 99.50wt%;

[0070] 2) Hydrogenation reduction: A 10 cm high platinum-carbon catalyst was filled into a titanium fixed bed reactor with a diameter of 30 mm and a length of 30 cm. After sealing, the preheater and the reactor were heated to 110°C. The residual liquid containing 2,3-dichloro-5-trifluoromethylaniline and hydrogen were simultaneously introduced into the titanium fixed bed reactor at a rate of 1.5 mL / min and 70 mL / min, respectively. The reaction pressure was adjusted to 0.20 MPa by a back pressure valve. The feed reaction was continued, and the 2,3-dichloro-5-trifluoromethylaniline in the reaction liquid was detected by sampling at the same time. The reaction is terminated when the qualitative content of fluoromethylaniline in gas phase is 0.45%. The reaction tail gas is first absorbed by water to obtain a byproduct hydrochloric acid with a purity of about 30wt%, and then the hydrogen is compressed and reused through drying and compression operations. The hydrogenation reduction material after the reaction is collected and distilled to obtain 11.61g of a m-trifluoromethylaniline product with a purity of 99.15wt%, and the yield of m-trifluoromethylaniline is about 18.00%. The platinum content in the platinum-carbon catalyst is 2.0wt%, and the particle size of the platinum-carbon catalyst is 0.5-1.0mm.

[0071] Example 4

[0072] A method for simultaneously preparing 2,6-dichloro-4-trifluoromethylaniline and m-trifluoromethylaniline, the specific steps comprising:

[0073] 1) Amination reaction: 100.00 g 3,4,5-trichlorobenzotrifluoride (0.40 mol) and 250.00 g N-propylpyrrolidone were mixed and added to an autoclave, 250.00 g ammonia (14.53 mol) was introduced, the temperature was raised to 170° C. and 9.0 MPa, and the reaction was carried out for 7 hours. The gas phase qualitative content of 3,4,5-trichlorobenzotrifluoride in the reaction solution was sampled and detected to be 0.75%. After the reaction was completed, the pressure was released, and the ammonia was compressed and reused; the reaction solution obtained after the pressure release was filtered;

[0074] The obtained filtrate was distilled to obtain 71.50 g of N-propylpyrrolidone and 73.28 g of 2,6-dichloro-4-trifluoromethylaniline with a purity of 99.20 wt %, and the remaining about 25.50 g of residual liquid containing 2,3-dichloro-5-trifluoromethylaniline was stored for later use; the yield of 2,6-dichloro-4-trifluoromethylaniline was 79.60%;

[0075] The obtained filter cake is dried to recover N-propyl pyrrolidone, and the obtained solid is dissolved in water, the amount of water added is twice the weight of the dried solid, and then the organic matter is adsorbed by XDA-1G resin, concentrated, filtered, dried, etc., to obtain a byproduct ammonium chloride with a purity of 99.50wt%;

[0076] 2) Hydrogenation reduction: A 15 cm high platinum-carbon catalyst was filled into a titanium fixed bed reactor with a diameter of 30 mm and a length of 30 cm. After sealing, the preheater and the reactor were heated to 115°C. The residual liquid containing 2,3-dichloro-5-trifluoromethylaniline and hydrogen were simultaneously introduced into the titanium fixed bed reactor at a rate of 2.0 mL / min and 80 mL / min, respectively. The reaction pressure was adjusted to 0.10 MPa by a back pressure valve. The feed reaction was continued, and the 2,3-dichloro-5-trifluoromethylaniline in the reaction liquid was detected by sampling at the same time. The reaction is terminated when the qualitative content of fluoromethylaniline in gas phase is 0.25%. The reaction tail gas is firstly absorbed by water to obtain byproduct hydrochloric acid with a purity of about 30wt%, and then the hydrogen is compressed and reused through drying and compression operations. The hydrogenation reduction material after the reaction is collected and distilled to obtain 11.70g of m-trifluoromethylaniline product with a purity of 99.20wt%, and the yield of m-trifluoromethylaniline is about 18.15%. The platinum content in the platinum-carbon catalyst is 2.5wt%, and the particle size of the platinum-carbon catalyst is 0.5-1.0mm.

[0077] Example 5

[0078] A method for simultaneously preparing 2,6-dichloro-4-trifluoromethylaniline and m-trifluoromethylaniline, the specific steps comprising:

[0079] 1) Amination reaction: 100.00 g 3,4,5-trichlorobenzotrifluoride (0.40 mol) and 300.00 g N-butylpyrrolidone were mixed and added to an autoclave, 270.00 g ammonia (15.70 mol) was introduced, and the temperature was raised to 175° C. and 9.5 MPa for reaction for 8 hours. The gas phase qualitative content of 3,4,5-trichlorobenzotrifluoride in the reaction solution was sampled and detected to be 0.20%. After the reaction was completed, the pressure was released, and the ammonia was compressed and reused; the reaction solution obtained after the pressure release was filtered;

[0080] The obtained filtrate was distilled to obtain 72.50 g of N-butylpyrrolidone and 72.80 g of 2,6-dichloro-4-trifluoromethylaniline with a purity of 99.10 wt %, and the remaining about 26.00 g of residual liquid containing 2,3-dichloro-5-trifluoromethylaniline was stored for later use; the yield of 2,6-dichloro-4-trifluoromethylaniline was 79.00%;

[0081] The obtained filter cake is dried to recover N-butylpyrrolidone, and the obtained solid is dissolved in water, the amount of water added is twice the weight of the dried solid, and then the organic matter is adsorbed by XDA-1G resin, concentrated, filtered, dried, etc., to obtain a byproduct ammonium chloride with a purity of 99.50wt%;

[0082] 2) Hydrogenation reduction: A 15 cm high platinum-carbon catalyst was filled into a zirconium fixed bed reactor with a diameter of 30 mm and a length of 40 cm. After sealing, the preheater and the reactor were heated to 120°C. The residual liquid containing 2,3-dichloro-5-trifluoromethylaniline and hydrogen were simultaneously introduced into the zirconium fixed bed reactor at a rate of 2.5 mL / min and 90 mL / min, respectively. The reaction pressure was adjusted to 0.25 MPa by a back pressure valve. The feed reaction was continued, and the 2,3-dichloro-5-trifluoromethylaniline in the reaction solution was detected by sampling at the same time. The reaction is terminated when the qualitative content of fluoromethylaniline in gas phase is 0.35%. The reaction tail gas is firstly absorbed by water to obtain byproduct hydrochloric acid with a purity of about 30wt%, and then the hydrogen is compressed and reused through drying and compression operations. The hydrogenation reduction material after the reaction is collected and distilled to obtain 12.00g of m-trifluoromethylaniline product with a purity of 99.10wt%, and the yield of m-trifluoromethylaniline is about 18.60%. The platinum content in the platinum-carbon catalyst is 3.0wt%, and the particle size of the platinum-carbon catalyst is 0.5-1.0mm.

[0083] Example 6

[0084] A method for simultaneously preparing 2,6-dichloro-4-trifluoromethylaniline and m-trifluoromethylaniline, the specific steps comprising:

[0085] 1) Amination reaction: 100.00 g 3,4,5-trichlorobenzotrifluoride (0.40 mol) and 200.00 g N-butylpyrrolidone were mixed and added to an autoclave, 225.00 g ammonia (13.08 mol) was introduced, the temperature was raised to 185° C. and 10.0 MPa, and the reaction was carried out for 5 hours. The gas phase qualitative content of 3,4,5-trichlorobenzotrifluoride in the reaction solution was sampled and detected to be 0.30%. After the reaction was completed, the pressure was released, and the ammonia was compressed and reused; the reaction solution obtained after the pressure release was filtered;

[0086] The obtained filtrate was distilled to obtain 72.00 g of N-butylpyrrolidone and 72.30 g of 2,6-dichloro-4-trifluoromethylaniline with a purity of 99.20 wt %, and the remaining about 27.00 g of residual liquid containing 2,3-dichloro-5-trifluoromethylaniline was stored for later use; the yield of 2,6-dichloro-4-trifluoromethylaniline was 78.50%;

[0087] The obtained filter cake is dried to recover N-butylpyrrolidone, and the obtained solid is dissolved in water, the amount of water added is twice the weight of the dried solid, and then the organic matter is adsorbed by XDA-1G resin, concentrated, filtered, dried, etc., to obtain a byproduct ammonium chloride with a purity of 99.50wt%;

[0088] 2) Hydrogenation reduction: A 15 cm high platinum-carbon catalyst was filled into a zirconium fixed bed reactor with a diameter of 30 mm and a length of 40 cm. After sealing, the preheater and the reactor were heated to 120°C. The residual liquid containing 2,3-dichloro-5-trifluoromethylaniline and hydrogen were simultaneously introduced into the zirconium fixed bed reactor at a rate of 3.0 mL / min and 100 mL / min, respectively. The reaction pressure was adjusted to 0.30 MPa by a back pressure valve. The feed reaction was continued, and the 2,3-dichloro-5-trifluoromethylaniline in the reaction liquid was detected by sampling at the same time. The reaction is terminated when the qualitative content of trifluoromethylaniline in gas phase is 0.30%. The reaction tail gas is firstly absorbed by water to obtain a byproduct hydrochloric acid with a purity of about 30wt%, and then the hydrogen is compressed and reused through drying and compression operations. The hydrogenation reduction material after the reaction is collected and distilled to obtain 12.44g of m-trifluoromethylaniline product with a purity of 99.20wt%, and the yield of m-trifluoromethylaniline is about 19.30%. The platinum content in the platinum-carbon catalyst is 2.5wt%, and the particle size of the platinum-carbon catalyst is 0.5-1.0mm.

[0089] Comparative Example 1

[0090] The platinum-carbon catalyst in Example 6 is replaced with a palladium-carbon catalyst, and the specific steps include:

[0091] 1) Ammoniation: 100.00 g 3,4,5-trichlorobenzotrifluoride (0.40 mol) and 200.00 g N-butylpyrrolidone were added to an autoclave, 225.00 g ammonia (13.08 mol) was introduced, the temperature was raised, and the reaction was carried out at 185° C. and 10.0 MPa for 5 hours. The gas phase qualitative content of 3,4,5-trichlorobenzotrifluoride was 0.30% after sampling and detection. After the reaction was completed, the pressure was released, and the ammonia was compressed and reused; after the pressure was released, the filtrate was filtered, and the ammoniation filtrate was distilled in sequence to obtain 72.00 g N-butylpyrrolidone, 72.30 g of 2,6-dichloro-4-trifluoromethylaniline with a purity of 99.20 wt%, the yield of 2,6-dichloro-4-trifluoromethylaniline is 78.50%, and the remaining about 27.00 g of residual liquid containing 2,3-dichloro-5-trifluoromethylaniline is used for hydrogenation reduction reaction; after the amination filter cake is dried to recover N-butylpyrrolidone, the solid is dissolved in 2 times the weight of water, and the organic matter is adsorbed by XDA-1G resin, concentrated, filtered, dried, etc. to obtain a byproduct ammonium chloride with a purity of 99.50 wt%;

[0092] 2) Hydrogenation reduction: A palladium carbon catalyst with a palladium content of 2.5 wt% and a diameter of 0.5-1.0 mm is filled into a zirconium reactor with a diameter of 30 mm and a length of 40 cm and a height of 15 cm. After sealing, the preheater and the reactor are heated to 120° C. The residual liquid containing 2,3-dichloro-5-trifluoromethylaniline and hydrogen gas enter the zirconium reactor at the speed of 3.0 mL / min and 100 mL / min respectively. The reaction pressure is adjusted to 0.30 MPa by a back pressure valve, and the feeding reaction is continued. The qualitative content of 2,3-dichloro-5-trifluoromethylaniline in the gas phase is detected to be 0.30% by the sample in a timely manner. The reaction tail gas is first absorbed by water to obtain a byproduct hydrochloric acid with a purity of about 30 wt%. After the water absorption, the hydrogen gas is compressed and reused by drying and compression operations. The hydrogenation reduction material after the reaction is completed is collected and distilled to obtain 3.68 g of a m-trifluoromethylaniline product with a purity of 99.05 wt%, and the yield of m-trifluoromethylaniline is about 5.7%.

[0093] After the catalyst was changed from platinum carbon to palladium carbon, the selectivity during hydrogenation reduction was poor, part of the fluorine was removed, and the yield of m-trifluoromethylaniline dropped significantly.

Claims

1. A method for simultaneously preparing 2,6-dichloro-4-trifluoromethylaniline and m-trifluoromethylaniline, characterized in that: The steps include: 1) Amination reaction 3,4,5-trichlorobenzotrifluoride is used as a raw material, mixed evenly with a pyrrolidone solvent, added to an autoclave, ammonia gas is introduced, the temperature is raised to the reaction temperature and then kept warm for reaction, the central control sampling is used to detect the gas phase qualitative content of 3,4,5-trichlorobenzotrifluoride in the reaction liquid is less than 1% to end the reaction, the pressure is released after the reaction is completed, and the reaction solution obtained after the pressure release is filtered to obtain a filtrate and a filter cake respectively; The obtained filtrate is filtered and distilled to obtain pyrrolidone solvent and 2,6-dichloro-4-trifluoromethylaniline in sequence, and the remaining residual liquid is stored for later use; The pyrrolidone solvent is at least one of N-methylpyrrolidone, N-propylpyrrolidone and N-butylpyrrolidone, and the amount of the pyrrolidone solvent is 1N3 times the weight of 3,4,5-trichlorotrifluorotoluene; The reaction temperature is 170N190°C, and the reaction pressure is 7-10MPa; The molar ratio of 3,4,5-trichlorotoluene trifluoride to ammonia is 1:25-40; 2) Hydrogenation reduction The residual liquid obtained in step 1) and hydrogen are simultaneously introduced into a fixed bed reactor adjusted to the reaction temperature and reaction pressure for hydrogenation reduction reaction, and during the reaction, samples are taken to detect the gas phase qualitative content of 2,3-dichloro-5-trifluoromethylaniline in the reaction liquid until it is less than 0.5%, and the hydrogenated material after the reaction is completed is collected and distilled to obtain a m-trifluoromethylaniline product with a purity of more than 99wt%; The fixed bed reactor is filled with a catalyst; The catalyst is platinum carbon, wherein the platinum content is 1-5wt% and the particle size of the platinum carbon is 0.5-1.0mm; The residual liquid feed rate is 0.5-3.0 mL / min, and the hydrogen feed rate is 50-100 mL / min; The reaction temperature is 100-120° C., and the reaction pressure is 0.1-0.5 MPa.

2. The preparation method according to claim 1, characterized in that: In step 1), the filter cake obtained by filtration is dried, dissolved in water, adsorbed by resin, concentrated, and dried to recover the byproduct ammonium chloride.

3. The preparation method according to claim 2, characterized in that: The resin is at least one of XDA-1G, XDA-6, XDA-8, and XDA-200, preferably XDA-1G.

4. The preparation method according to claim 2, characterized in that: The amount of water added for dissolution is 2 to 5 times the weight of the filter cake after drying.

5. The preparation method according to claim 1, characterized in that: In step 1), the reaction time is 5 to 10 hours.

6. The preparation method according to claim 1, characterized in that: In step 1), ammonia gas is collected during the pressure release process and compressed for reuse.

7. The preparation method according to claim 1, characterized in that: In step 2), the fixed bed reactor is made of one of Hastelloy, titanium and zirconium, the reactor diameter is 30-40 mm, the length is 30-40 cm, and the platinum carbon filling height is 10-15 cm.

8. The preparation method according to claim 1, characterized in that: In step 2), the reaction tail gas is first absorbed by water to obtain by-product hydrochloric acid, and then dried and compressed to compress the hydrogen for reuse.

9. The preparation method according to claim 8, characterized in that: The purity of the obtained by-product hydrochloric acid is 28wt% to 31wt%.

Images